The BBC series about a time-traveling humanoid known as the Doctor will celebrate its 50th anniversary on Nov. 23, with a special episode called "The Day of the Doctor."

In advance of the occasion, producers cut together a special teaser including material from all 11 actors who have played the Doctor (the 12th, Peter Capaldi, will premiere in the Christmas special). The trailer was shown to fans at a Comic-Con session in July, but producers have otherwise kept it under wraps.